1. Field
Example embodiments relate to group III-V compound semiconductor-based photodiodes, image sensors including the photodiodes, and/or methods of manufacturing the photodiodes and the image sensors.
2. Description of the Related Art
An image sensor is a semiconductor device that converts an optical image to an electrical signal and that is typically used in various fields such as cameras, motion recognition cameras, and touch panels.
The image sensor includes a light receiving element that senses light and converts the light to an electrical signal and a readout circuit that processes the electrical signal to form the same to data.
A photodiode based on a group III-V compound semiconductor is used as the light receiving element of the image sensor, and a silicon-based readout integration circuit (ROIC) is used as a readout circuit of the photodiode.
To implement an image sensor including the silicon-based readout integration circuit (ROIC) and the photodiode based on a group III-V compound semiconductor, a hybrid structure or monolithic structure may be employed.
According to the hybrid structure, a photodiode and a readout circuit are manufactured on different wafers and are then bonded. Thus, a number of complicated manufacturing processes are used, and it is often difficult to align the photodiode and the readout circuit.
According to the monolithic structure, a single wafer is divided into areas to manufacture a photodiode and a readout circuit on the wafer. With the increase in a resolution of an image sensor, a pixel size is reduced, and accordingly, a light receiving area in a pixel is also reduced. Moreover, since it is difficult to reduce a size of the readout circuit, a ratio of the light receiving area in the pixel is gradually reduced as the pixel size is reduced. Accordingly, in order to provide a high image quality and a high resolution, the light receiving area in the pixel may be increased.